Much evidence on the issue of fox-hunting with hounds is either speculative, being based on questionnaire surveys, or contradictory, particularly where funds are provided by special-interest groups. The recent study done at Bristol University (P. J. Baker, S. Harris & C. J. Webbon, Nature 419, 34; 2002) is noteworthy for attempting an experimental approach.

Baker et al. found that the temporary cessation of fox-hunting in Britain during the foot-and-mouth disease outbreak of 2001 had no impact on fox population density, and concluded that a permanent ban on hunting is unlikely to result in a dramatic increase in fox numbers. However, motor vehicles are the greatest killer of foxes in Britain, accounting for some 25% of deaths. Hunting with hounds accounts for only 6.3% of the 400,000 foxes killed annually. More than five times as many are killed by shooting and snaring as by hunting with hounds in lowland hunting areas (L. Burns, V. Edwards, J. Marsh, L. Soulsby & M. Winter. Report of the Committee of Inquiry into Hunting with Dogs in England and Wales, Stationery Office, London; 2000; see Fox-hunting is an ineffective method of population control.

Instead, these data suggest that fox-hunting harvests a sustainable off-take, which might represent a traditional form of community-based conservation. Such projects improve local tolerance towards wildlife and maintain biodiversity without statutory regulation and recurrent public funding. The British government has supported many such projects in developing countries, and is committed to doing the same in Britain as a signatory to the Convention on Biological Diversity.

The defence of fox-hunting on conservation grounds relies on two main predictions in the event of a ban: first, that voluntary maintenance of biodiversity-rich fox habitats such as woodlands and hedgerows by landowners involved in hunting would decline; second, that landowners' tolerance of foxes would decline, increasing their persecution by other potentially less humane methods and so reducing fox numbers. Landowners may have the potential to reduce fox densities by shooting and snaring (M. Heydon & J. Reynolds, J. Zool. 251, 265; 2000), but using these results to predict changes after any ban remains problematic.

The best way to test these predictions would be to build on the opportunistic approach attempted by Baker et al. by imposing a temporary, medium-term ban in randomly chosen areas and conducting independently funded research into its effects on a range of factors. This adaptive management approach would satisfy Lord Burns's recent recommendation not to rush a decision on whether to ban hunting. Although this approach has its pitfalls, we believe that, with careful planning, it would provide a firmer scientific basis for legislation than existing evidence.